Intolerance means refusing to accept or respect people, ideas, or behaviors that are different from your own. When someone shows intolerance, they treat others unfairly simply because those people believe differently, look different, or make choices they disagree with.

The word often appears in discussions about how people treat each other in communities and societies. Religious intolerance means refusing to accept people who follow different faiths. Political intolerance means dismissing or attacking people who hold different political views instead of listening to their reasoning.

The word can also be used in a medical sense, such as food intolerance or pharmaceutical intolerance. This means that a person's body can't handle that food or medicine. Someone with a gluten intolerance gets sick when they eat gluten and should avoid it.